icecc: don't create unnecessary 'ice' dirs in sysroots when disabled
* parsing ICE_PATH="${@icc_path(bb, d)}" causes "ice" directories
to be created in every sysroot, that could be a bit confusing for
people who inherit icecc.bbclass, but disabled it
* shorten ICECC_VERSION="${@icc_version(bb, d)}" path a bit
by returning sooner when disabled
* remove ICECC_PATH and ICECC_ENV_EXEC from signatures, we assume that
using icecc doesn't influence the output, so it shouldn't matter when
user supplies own version of icecc or env script
* always compare ICECC_DISABLED with "1", boolean typed_value isn't used
because documentation already mentions using empty value to keep icecc
enabled and that's not valid boolean value when oe.data.typed_value is
used:
ERROR: ICECC_DISABLED: Invalid boolean value ''
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
